REVIEW OF AUTOGENOUS AND AUTONOMOUS SELF-HEALING CONCRETE TECHNOLOGIES FOR MARINE ENVIRONMENTS MARWAN SUHAIL SUNAKH ZABANOOT Department of Architecture and Civil Engineering, University of Bath, UK ABSTRACT Most structures use concrete as a main material in their construction work. Despite its low cost and high compressive strength properties, it suffers from disadvantageous cracks on surfaces when it is hardened, which be costly to repair. Europe spends almost half of its construction budget annually on structure repairs. Fortunately, today’s science had reached a level of engineered solutions to experimentally overcome this dilemma. In order to reduce the repair expenses of concrete cracks, a solution of self-healing concrete is introduced. The process of self-healing cracks in hardened concrete depends on including – in most cases – agents in the cementitious compositions such as minerals, bacteria and microcapsules containing adhesive materials. The actual challenge to be faced is when it comes to concrete construction in marine environments like seashores, such aggressive mediums uncover various considerations due to the biological and chemical behaviors in those places. This paper aims to provide a literature body based on research to review different types of self-healing technologies and their durability for reinforced concrete (RC), especially for structures in marine environments in both approaches: autogenous and autonomous. As seen from the literature body, the concluded methods for healing concrete cracks include the Ground Granulated Blast Furnace Slag (GGBFS), partially substituted with cement in the mixture. In addition to that, the utilization of the autonomous Bactria-based self-healing is another smart method that the literature lately revealed. Keywords: self-healing concrete, autogenous, autonomous, marine environments, GGBFS, SAP particles, polyurethane. 1 INTRODUCTION According to Joshi et al. [1], “As nearly 80% of world’s infrastructure is built in reinforced concrete, their maintenance needs a huge recurring investment that few countries in the world can afford. There is a worldwide effort for sustainable technologies for maintenance of infrastructures that would offer economy without undue environmental or social costs” [1]. Marine environment is considered an extreme and aggressive environment for establishing concrete structures. Such environments require special precautions and engineered procedures for the reinforced concrete to withstand, for example, the low temperatures of sea water, tidal effects, pressure, biological life, etc. Marine environments contain high percentages of chloride concentration. The reinforced concrete is the type of structure used in such environments. The durability of reinforced concrete is affected negatively by chloride as it is harmful due to corrosion affect. When cracks occur in RC in marine environment, that will facilitate the penetration of chloride into the hardened material which will make the corrosion even faster [2]. As noticed, cracks in concrete structures in sea environments have the major cause for initiating a continuous damage to the internal parts of the structure. The extent to which the chloride penetration into the cracks can reach, is dependent on several variables. For example, width and depth of the crack itself. Also, the type of cementitious mixture and its composition [2]. Aggressive agents such as Chloride, Magnesium and Sulfate can damage the solid concrete and eventually will lead to shortening its service life [3]. Essentially, the sizes of the cracks in the concrete are playing a crucial role as that is main interface for ingress of any liquids or chemical particles to the inside. “To limit the crack High Performance and Optimum Design of Structures and Materials IV 31 www.witpress.com, ISSN 1743-3509 (on-line) WIT Transactions on The Built Environment, Vol 196, © 2020 WIT Press doi:10.2495/HPSM200041
REVIEW OF AUTOGENOUS AND AUTONOMOUS SELF-HEALING CONCRETE TECHNOLOGIES FOR MARINE ENVIRONMENTS
May 01, 2023
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